Grigoriy Sisoev/Host Photo Agency via Getty Images(WASHINGTON) -- If Syrian President Bashar al-Assad gives up his chemical weapons, a military strike would "absolutely" be on pause, President Obama said Monday.

"I consider this a modestly positive development," Obama told ABC News' Diane Sawyer in an interview at the White House when asked whether Syria's apparent willingness to relinquish control of its chemical weapons would prevent a U.S. strike.

"Let's see if we can come up with language that avoids a strike but accomplishes our key goals to make sure that these chemical weapons are not used," the president said.

Obama's comments come after the Russian foreign minister suggested Monday that Syria could avoid a U.S. attack by turning over its chemical weapons stockpiles over to international control and destroying them, a proposal the Syrian government "welcomed."

Obama said that Secretary of State John Kerry would pursue the proposal with Russia, an ally of Syria.

But at the same time, Obama said that a potential diplomatic resolution doesn't mean that Congress should withdraw the threat of military action.

"I don't think we would have gotten to this point unless we had maintained a credible possibility for a military strike and I don't think now is the time for us to let up on that," Obama said.

Assad is accused of using chemical weapons against his own people on a small scale "multiple times" since March and, according to the White House, an Aug. 21 attack on Damascus claimed 1,400 lives, 400 of them children.

Since then, Obama and his aides have worked feverishly for more than a week to build congressional support to strike Syria.

On Monday alone, more than 70 lawmakers of both parties came through the White House for briefings with the president's top advisers.

But while many lawmakers remain undecided, growing numbers are opposed to the use of force.

Obama suggested that Syria's willingness to pursue a diplomatic solution could give Congress more time to decide on whether to grant him the authority to strike.

"I don't anticipate that you would see a succession of votes this week or anytime in the immediate future," Obama said. "So I think there will be time during the course of the debates here in the United States for the international community, the Russians and the Syrians to work with us and say is there a way to resolve this."

And a new ABC News/Washington Post poll Monday found nearly two-thirds of Americans oppose military action in Syria.

Obama said he understood the "skepticism" of members of Congress and the American public, but he warned that U.S. national security interests are at stake if Syria is allowed to use "one of the world's worst weapons" without consequences.

"I would prefer not having to do it but I think it is important for us to understand that if in fact the choice is between a world in which dictators and other countries believe it is acceptable to use chemical weapons on civilians and children, that will make it more dangerous for us," Obama said.